This reverts part of 1f1810c37d in #5959.

Leaving the main thread unnamed causes it to be displayed as the executable name (i.e. `zcashd`)
or command line in process monitoring tools. fixes #6066

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

src/bitcoind.cpp

@@ -43,10 +43,6 @@ static bool fDaemon;
 
 void WaitForShutdown(boost::thread_group* threadGroup)
 {
-    // This is the main process thread, but after this point, all we do here is wait for
-    // shutdown, and then shut down the node.
-    RenameThread("zc-wait-to-stop");
-
     bool fShutdown = ShutdownRequested();
     // Tell the main threads to shutdown.
     while (!fShutdown)